The present invention relates to a method and an apparatus for the production of liquid iron, especially for directly producing liquid iron from iron ore.
Many attempts have already been made for producing liquid iron directly from iron ore.
Thus a method has been disclosed wherein the iron ore is first transformed into sponge iron by means of a suitable gas, whereafter the sponge iron is melted in a metallurgical container, whereby by a reaction of oxygen-containing gases with carbon-containing substances, which are blown into the container beneath the surface of the bath, heat energy as well as carbon monoxide are formed. The heat energy is in part used to melt the sponge iron and the exhaust gas is used for the reduction of ore. In this method it is necessary to treat the exhaust gas in a separate reactor with coal dust and water vapor.
According to another known method, which serves to produce steel from iron ore without a separate pig iron phase, a reducing gas is produced by reacting a fuel with oxygen in a combined melting and gas-producing reactor and the reducing gas is then guided in countercurrent direction to a stream of iron ore in an adjacent reduction space in which the pre-reduced ore at the end of the reduction step is transported into the heated melting and gas-producing reactor to be melted therein and subsequently be completely reduced.
In another known method directed to produce directly pig iron from iron ore, there are provided two separate charging, respectively reaction zones in a melting and gas-producing reactor. In a first zone a carbon carrier is directly introduced into the bath to maintain therein a melt with a carbon content of preferably over 2%. In a second zone bordering the first one, a part of the carbon contained in the melt is burned by means of oxygen, whereby heat and reducing gases are released. The carbon introduced through a lance is therefore in this method used for increasing the melting capacity of the bath and for producing of reduction gases.
The production of strongly reducing gases during a combined reduction and melting process requires, however, extensive and complicated controls in order to assure that the process proceeds in the desired manner, if it is not preferred that the obtained exhaust gas is separately treated in order to obtain therein a sufficient reduction potential.